Tea and instant tea in solid form — Determination of caffeine content — Method using high-performance liquid chromatography

The method specified is based on extracting the caffeine from a test portion with water at 90 °C in the presence of magnesium oxide, filtration followed by determination of the caffeine content by HPLC with UV detection. Applies to teas and instant teas with a caffeine content of greater than 0,3 % (m/m).